How to create an engine glow effect for spaceships in cycles?
There could be several ways to do this.

If you don't want to gent into full rendering just switch to Blender Internal rendering and create either a shadeless material or an emitting material and assign it to parts of your mesh. It wot actually emit light that can cast shadows on other objects but it will quickly simulate the effect.



You could also add some sort of "geometry plumes" if you want actual jet plumes coming out.



If you plan on using cycles or do real rendering add self illumination to the geometry to really light up the scene

Any further effects could be achieved through compositing or post production easily and non destructively